If you're looking for 520 front sprockets for the 70h V3 the best two options are:
Lithium King (based in Florida) which is what I have. They have 12t, 13t and 14t.
Lithium King | EV Parts, Batteries, Conversions Kits
MightE (based in the UK). They have 12t, 13t, 14t and 15t.
13t 520 pitch...